Liquefied natural gas, referred to in abbreviated form as “LNG,” is a natural gas which has been cooled to a temperature of approximately −162 degrees Celsius with a pressure of up to approximately 25 kPa (4 psi) and has thereby taken on a liquid state. Most natural gas sources are located a significant distance away from the end-consumers. One cost-effective method of transporting natural gas over long distances is to liquefy the natural gas and to transport it in tanker ships, also known as LNG-tankers. The liquid natural gas is transformed back into gaseous natural gas at the destination.
In a typical liquefaction process a compressor is used to deliver pressurized refrigerant to a cold box, which in turn is used to cool a feedgas, such as a natural gas, to form a liquefied gas. The compressor is typically driven by a motor. Most motors need to be cooled and that may limit the maximum power that the motor can generate. Cooling a motor requires energy and resources which can be expensive and can take up considerable space. Therefore, there is a need for methods and processes for improving the cooling of a motor that drives a compressor that is used in a liquefaction process.